Surface mines and similar sites or areas are generally operated by means of a large number of vehicles, some of which may be exceedingly large and difficult to control and have very limited visibility for the operator.
It has been proposed to use GNSS-devices (GNSS=global navigation satellite system, such as GPS) on board of the vehicles and other objects, such as cranes, to generate proximity warnings in order to reduce the risk of collisions between vehicles. Such a system is e.g. described in WO 2004/047047. The system is based on devices mounted to the objects. Each device comprises a GNSS receiver, a control unit deriving positional data using the signal of the GNSS receiver, a radio circuit for wireless exchange of the positional data with the other devices, and an output device for outputting proximity warnings.
Depending on the types of vehicles, such systems can become very complex or inaccurate. This is, in particular, true for highly asymmetric, large vehicles whose orientation in space may change. I.e. for rotating and/or track type vehicles, a proximity warning system needs to take the orientation of the vehicle into account, as deriving the vehicle's orientation through translatory motion is not possible or not sufficiently accurate or fast.